<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
            /* 一个冒号是伪类 两个冒号是伪元素 */
            .box::before{
                content: "我";
                /* 因为是行内元素所以无法设置宽高 */
                display: inline-block;
                width: 30px;
                height: 30px;
                background-color: pink;
            }

            .box::after{
                content: "刘德华";
            }
    </style>
</head>
<body>
    <div class="box">是</div>
</body>
</html>